鲫鱼视网膜锌离子分布的光、电镜观察

LIGHT AND ELECTRON MICROSCOPIC OBSERVATION OF ZINC DISTRIBUTION IN THE CARP RETINA *

本文应用ｎｅｏＴｉｍｍ染色法，观察了鲫鱼视网膜内锌离子的分布情况以及明、暗适应条件下鲫鱼视网膜内锌离子分布的变化。结果发现：明适应条件下，外网层、部分光感受器、双极细胞、无长突细胞以及神经节细胞胞体锌离子着色明显。含锌光感受器和双极细胞的突起伸入外网层。暗适应条件下，外网层锌离子染色减弱抑或消失（Ｐ＜００１）。外核层胞体锌离子染色阴性，少数散在分布的视锥细胞呈锌离子阳性。上述资料提示，明适应条件下外网层视觉通路１、２级神经元之间突触组构区存在锌离子，并在暗适应条件下释放，为锌离子在视网膜内信号调制中起重要作用提供了形态学证据。

Localization of zinc in the carp retina in both light and dark adaptation was investigated using neo Timm sulfate silver method. The results showed that in light adaptation, zinc was preponderantly present in the outer plexiform layer (OPL). Both terminals of zinc containing photoreceptors and dendrites of bipolar cells usually extend into zinc staining areas in OPL. In dark adaptation, zinc staining in retina is blanched or only appeared in cytoplasmic bodies of few cones. There is no significant difference between dark and light adaptation in the zinc distribution in bipolar, amacrine and ganglion cells. The fact that zinc is perched in the carp retina between photoreceptors and second order neurons of the visual pathways in OPL in light adaptation and significantly released in dark adaptation suggests that zinc might play some modulatory roles in the visual signal transduction.